Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Adds a non-annotation behavioral trait: 'Costs 1 credit', which is not in the annotations. Also describes the output ('per-step breakdown and optimization suggestions'), adding context beyond the idempotentHint and destructiveHint annotations. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the primary purpose. Each sentence adds distinct value: purpose, return value, and conditional alternative with cost. No fluff or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity, the description adequately covers the use case, output, and costs. The schema and output schema handle parameter and result details, so the description is sufficient. Could be more complete with e.g. explanation of 'credit', but not necessary.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema covers 100% of parameters with descriptions, so the description does not need to add parameter-level detail. The description only refers to the 'multi-step agent plan' conceptually, without explaining parameter syntax or semantics beyond what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's function: 'estimate the total LLM cost' for a 'multi-step agent plan' before execution. It also mentions the return of a per-step breakdown and optimization suggestions, distinguishing it from a generic estimation tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states when to use: 'Before executing a multi-step agent plan'. Provides an explicit alternative: 'If the estimate exceeds your budget, pipe the same plan into burnrate_optimize'. This gives clear context and a condition for switching to a sibling tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.